1. Field of the Invention
Embodiments of the present invention generally relate to a shield assembly for use in a vacuum chamber.
2. Description of the Related Art
In semiconductor processing, particularly physical vapor deposition, a vacuum chamber is used to deposit materials onto a surface of a substrate that is supported by a substrate support member. A target, typically made of materials such as titanium, aluminum, or copper mounts on a backing plate located in the upper portion of the vacuum chamber that is supplied with an inert gas, such as argon. A DC or RF voltage is applied to the target to generate a plasma in an area between the substrate and the target to produce ions, which bombard the target, and result in the sputtering of target material onto the substrate. However, the target material also deposits on the chamber walls and chamber components, such as the substrate support member, and become a source of contaminants. The target materials can build up and eventually flake off and fall onto the substrate, which can create defects in the substrate.
Conventional methods to clean vacuum chambers include wet cleaning processes and dry cleaning processes using a cleaning gas to react with the deposits. In this method, the deposition process must be discontinued during the cleaning process, and additional time is required for the cleaning materials and by-products to be evacuated from the chamber before the depositing process can resume.
Another conventional method includes using sputtering shields coupled to an adapter ring to prevent sputtering materials from depositing directly onto the chamber wall and other chamber components. A cover ring (shield) can also be provided to protect the substrate support surface from the sputtered materials. The shields are known as xe2x80x9cconsumablesxe2x80x9d and require periodic replacement to remove any buildup on them. In order to remove conventional sputtering shields from the adapter ring, other components, such as the insulators, o-rings, and clamp screws have to be disassembled and removed from the vacuum chamber. After the components are disassembled and removed, the used shields are replaced with new shields, and all of the components must be reassembled in the correct order and in the correct alignment to ensure that the vacuum chamber is vacuum-sealed. Thus, there is a significant downtime of the vacuum chamber in order to remove the consumables, replace them, and reassemble the components. With the frequent disassembly and assembly of the components to replace the shields, the screws and the components can rub against each other and generate contaminants in the vacuum chamber and cause defects on the substrate.
Therefore, there is a need for a removable shield assembly that is preferably easy to remove from the processing chamber, requires less substrate processing downtime, and decreases contamination of the chamber.
The present invention generally relates to a unitary removable shield assembly for use in a semiconductor processing system. The shield assembly can include an upper adapter assembly, at least one shield member affixed to an upper end of the upper adapter assembly, a cover ring detachably positioned on a lower portion of the shield member and an insulator member attached to the upper end of the upper adapter assembly. The upper adapter assembly may be sized to be received by an upper annular wall portion of a vacuum chamber, may be annularly shaped, and may have at least one shoulder configured to secure at least one shield member. The shoulder portion can include at least one nut plate configured to receive shield-securing bolts. The insulator member can include an annularly shaped member manufactured from an electrically insulative material, an annularly shaped dark space shield extending outwardly therefrom, and can be sized to receive a processing target. The at least one shield member may include an outer shield member and an inner shield member concentrically positioned within the outer shield member. The outer shield member can be cylindrically shaped and can include a plurality of radially positioned apertures formed therethrough. The covering ring may include an annularly shaped member having at least one channel formed into an under surface thereof and the channel configured to receive a flange member extending from the lower portion of the at least one shield member. The cover ring can further be configured to engage an outer portion of a substrate support member when the support member is raised into a processing position. The upper adapter assembly, the at least one shield member, the cover ring, and the insulator member can be configured to be removed from the semiconductor processing system as a unitary assembly.
In another embodiment, the unitary removable shield member can include a chamber insulator and an adapter member affixed to and positioned below the chamber insulator, an inner shield member affixed to the adapter member and extending downwardly therefrom, an outer shield member affixed to the adapter member and extending downwardly therefrom, the outer shield member may have at least one hole formed therein to allow process gases to pass therethrough, and a cover ring detachably positioned on a lower portion of at least one of the outer shield member and the inner shield member, the cover ring being configured to engage a periphery portion of a substrate support member when the support member is moved into a processing position. The adapter member can include an annularly shaped member having at least one shoulder member extending inwardly from an inner wall of the adapter member. The shoulder member can also be configured to receive and secure at least one of the chamber insulator, the inner shield member, and the outer shield member thereto. The inner shield may include a cylindrically shaped shield member having an upper flange member extending radially outward therefrom, the upper flange member being configured to attach to the at least one shoulder member. The outer shield member may include a cylindrically shaped shield member having a diameter that is greater than a diameter of the inner shield member, the outer shield member having an upper flange member extending radially outward therefrom, the upper flange member being configured to attach to the at least one shoulder member. The inner shield member may be configured to cover the at least one hole formed into the outer shield member, such that matter deposited onto a substrate positioned within the inner shield does not travel through the at least one hole formed into the outer shield. The cover ring may include an annularly shaped member having a lower surface configured to engage the substrate support member when the substrate support member is moved into the processing position, and engage a lower portion of at least one of the inner shield member and the outer shield member when the substrate support member is moved into a non-processing position. The cover ring can further include an annular grove formed into the lower surface, the annular groove being configured to receive a lower flange portion of at least one of the inner shield member and the outer shield member. The cover ring can also include a shoulder member positioned on an inner periphery portion of the cover ring, the shoulder member being annularly shaped and configured to engage the substrate support member when the substrate support member is moved into the processing position. The chamber insulator, the adapter member, the inner shield member, the outer shield member, and the cover ring are configured to be cooperatively removed from the semiconductor processing system with a unitary lift operation.
In a further embodiment, a physical vapor deposition system is provided and can include a processing chamber having a bottom, a sidewall, and a closable lid member having a physical vapor deposition target positioned on a lower surface of the lid member, a substrate support member positioned in the processing chamber and being configured to support a substrate for processing thereon, the substrate support member being selectively adjustable along a substantially vertical axis; and a unitary shield assembly that may include an insulator configured to electrically isolate the unitary shield member from electrical potentials in the physical vapor deposition system, an adapter member affixed to a lower surface of the insulator, an inner shield member affixed to the adapter member and extending downwardly therefrom, an outer shield member affixed to the adapter member and extending downwardly therefrom, the outer shield member being concentrically positioned outwardly from the inner shield member; and a cover ring detachably positioned on a lower portion of at least one of the outer shield member and the inner shield member, the cover ring being configured to engage a periphery portion of the substrate support member when the substrate support member is moved into a processing position. The outer shield member also include at least one hole formed therein, the at least one hole being configured to allow a process gas to travel therethrough toward an interior portion of the physical vapor deposition system.